Bottle Organ
Different notes come from different air-space lengths.
Teaching & key ideas
What you do: Blow across bottle tops.
What students see: Different notes come from different air-space lengths.
Why it works: The air column resonates; more water means a shorter air column and higher pitch.
Question to ask: How is this different from tapping the bottles?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: How is this different from tapping the bottles?